Traditional internal combustion engines, and in particular Diesel engines, have an engine block defining one or more cylinders each having a piston coupled to rotate a crankshaft. A cylinder head cooperates with the piston to define a combustion chamber. Fuel combustion in the combustion chamber generates a significant amount of exhaust gas that is directed into an exhaust system.
The exhaust system may include an exhaust pipe having one or more exhaust aftertreatment devices, among which a Diesel Particulate Filter (DPF) may be provided, namely a device designed to remove diesel particulate matter or soot from the exhaust gas of the engine.
More specifically, in some engines the DPF is mounted very close to the engine block giving rise to a configuration also known as close coupled DPF (CCDPF).
Current Diesel engine architectures equipped with CCDPF devices monitor the soot accumulation in the DPFs through a pressure drop measurement within the DPF devices themselves.
This measurement is done by a comparison between an upstream DPF pressure signal and a downstream DPF pressure signal.
The upstream DPF pressure signal is detected by means of an upstream pressure line that connects an upstream pressure port of the DPF to the exhaust pressure sensor. The downstream DPF pressure signal is detected by means of a downstream pressure line that connects a downstream pressure port of the DPF to the exhaust pressure sensor.
These pressure line connections form an exhaust pressure line and the whole exhaust pressure line is located externally with respect to the engine block perimeter.
The pressure lines are made by metal (generally stainless steel) and are fixed to the engine block by fixation points or by dedicated brackets in such a way to create a slope that guarantees that the pressure line is horizontal or downward oriented from exhaust pressure sensor to CCDPF pressure ports, in order to avoid water or moisture accumulation in the lines.
The connections between the metal pipe pressure line and the CCDPF pressure port (exhaust side) and the exhaust pressure sensor (sensor side) are made by plastic or rubber hoses designed to withstand the maximum operating temperatures and to guarantee the sealing of the connections.
Known pressure lines are configured with a minimum length to guarantee a temperature reduction of the exhaust gas before the pressure measurement inside the dedicated sensor.
The exhaust pressure sensor is located in a cold area of the engine compartment, which is normally the engine intake side area, to guarantee that the maximum operating temperature of the sensor, which is generally lower than 130° C., is not exceeded.
This conventional solution has several drawbacks.
A first drawback is that the external metal pipes and the relative brackets have a relevant cost.
A second drawback is that, since the exhaust pressure sensor is in an elevated position to guarantee a certain slope for the pressure line and since the pressure line crosses a region of the engine compartment in which many devices and connections are present, the design of a pressure line according to the prior art has a considerable complexity that also has a negative impact on costs.
At least one object of an embodiment disclosed is to overcome the above mentioned drawbacks by a pressure line for an internal combustion engine that guarantees substantial costs savings in design and production.
Another object is to provide an improved pressure line in an internal combustion engine in a simpler and more rational way.
In addition, other objects, desirable features and characteristics will become apparent from the subsequent summary and detailed description, and the appended claims, taken in conjunction with the accompanying drawings and this background.